Some stabilizers and wings of conventional aircraft include a panel (e.g., an edge panel) coupled to the skin of a stabilizer box or wing box. For skins made of metal, some aircraft machined recesses in the skins to receive the panel. However, for skins made of a non-metal, such as a fiber-reinforced polymer material, machining recesses into the skins is impractical due to the potential degradation of the fibers.
One known solution for coupling skins and panels made of fiber-reinforced polymer materials is to indirectly couple the skin of the stabilizer box and the panel with an adapter piece that extended between the panel and the skin (e.g., box skin). Fasteners secured the adapter piece to the panel and separate fasteners secured the adapter piece to the skin. The adapter piece and additional fasteners required to implement this solution added weight and cost to the aircraft.
Another solution aimed to eliminate the adapter piece and reduce the number of fasteners for coupling together skins and panels made of fiber-reinforced polymer materials included the placement of a toughened, low density filler in a gap between the skin and a shallow-angled portion of the panel. The toughened, low density filler is difficult to work with, has a low durability, and is susceptible to damage.